what is

criteria

i don't understood that part, please explain

a list of functions that you pass a Rating in and get a Float out

thanks @jon.peterson

does it(code you provided) have better performence than my code ?

nope. technically worse because it’s mapping before filtering 0's. that said, unless you have a million ratings in your list, I’m guessing you’re not going to see more than 1ms difference

I have gradle/groovy + multi-platform working. I have gradle/kotlin-dsl working. I do not have working code for gradle/kotlin-dsl + multi-platform

folks... quick question on (perhaps my understanding of)

reduce

. What would you expect this to print?

val fruitBasket = listOf("banana", "cherry", "orange", "apple", "banana", "cherry", "orange", "apple", "fig", "cherry")

fruitBasket.reduce { acc, s ->
    println(s)
    acc
}

Print all items except the first one?

That is what I am seeing, but I don't really understand why it doesn't print the first one

Cause

reduce

takes the first item as the first

acc

use fold with default acc value to avoid this behaviour

But you never print

acc

, so the first one is missing.

ahh... I hand't realised it did that... but it makes sense.. so if I were to use

fold

instead, it would print the first value as I'd pass an initialiser right?

Yes

i.e.

val fruitBasket = listOf("banana", "cherry", "orange", "apple", "banana", "cherry", "orange", "apple", "fig", "cherry")

fruitBasket.fold(0) { acc, s ->
    println(s)
    acc
}

Exactly

fold

also let you collapse into a different type, while

reduce

can only be the same type as the

List

gotcha! Yeah, that's good advice, thanks

I've a when condition with multiple options. For each mapping i need to do something but I've a special case (else) that i need to map to something else... This is the pseudo-code I currently have (I've just replaced the real options I have and replaced it with dummies. Is there a way to avoid the definition of

call

and concatenate directly after

when

? Something like this pseudo code

return when (it) { ... }?.subscribeOn(<http://Schedulers.io|Schedulers.io>())?.toObservable() else Observable.empty<String>()

A file was commented on

return when() {}

is valid

I think you need to put that inside the

when

seems to be due to nullability in my type.

it.baz

is nullable (probably a java pojo); the definition is

myfunc <T> (func Function<Foo, T>) : T?

Hi. I have a test-app written in kotlin and I've used jruby there. When I pass a java-

Map

to ruby, then I get back a java-

Map

, when I invoke some funktion in ruby. When I constuct a hash in ruby, it's a

RubyHash

passed back to kotlin. Now, since both types are possible and a

RubyHash

does not derive from java-

Map

, I get the

(TypeError) failed to coerce java.util.LinkedHashMap to org.jruby.RubyHash

error. Can I attack this with kotlin?

Does anyone have IntelliJ -> Tools -> IDE Scripting Console -> Kotlin working ? 1. I can'\t find any documentation on this. 2. From trying random stuff, I get either syntax errors or hang the system when I try to import a large package.

The context here is that I want to be able to extend IIntelliJ with kotlin fragments similar to how one can extend Emacs with Elisp fragments.

Does Kotlin support: https://en.wikipedia.org/wiki/Functional_reactive_programming ? When I try googling for it, I keep on getting videos on doing "functional programming in Kotlin" -- but the reactive part is really important Context: I'm using Kotlin/JS. My favorite for avoiding callback hell in async programming is to use FRP.

I think the Kotlin solution to callback hell is coroutines.

I don't mind co-routines. I can build on top of them. My main concern is: all the gradle files I have seen involving coroutines marks it as an experimental feature.

Yea could be, I don't know what functional reactive programming is really.